1. Field of the Invention
The present invention relates to a signal power detection device and a frequency analysis apparatus using the same, and more particularly to a card-type signal power detection device which has a low-noise amplification function therein and is capable of receiving a low-power signal and detecting the power of the received signal, and a frequency analysis apparatus which is capable of analyzing the frequency of the received signal under the condition that the card-type signal power detection device is mounted to a portable terminal device.
2. Description of the Related Art
Generally, in order to maintain the optimum propagation environment in a radio communication environment, base station and repeater operators have constructed and used apparatuses for frequency analyses of signals in a radio communication field.
It is common that such a signal frequency analysis is accomplished by the provision of a frequency analysis apparatus and a portable terminal device, such as a notebook computer, which is connected to the frequency analysis apparatus via a cable or the like and has a display unit for providing a visual indication of states analyzed by the frequency analysis apparatus. In this regard, it is difficult for only one person to conduct a system operation/maintenance with the above two units (frequency analysis apparatus and notebook computer) on the spot, so a duo generally conducts the system operation/maintenance with the two units on the spot. In particular, it is very dangerous for persons to get to and work upon a base station pylon with the two units as stated above.
Moreover, in order to analyze a signal with very low power, a low-noise amplifier must be mounted to the frequency analysis apparatus in addition to existing equipment. In this case, a separate power supply is further required to supply power to the low-noise amplifier. Such a frequency analysis system comprises an antenna 110, a low-noise amplifier 120, a frequency analysis apparatus 130 and a power supply 140, as shown in FIG. 1.
Accordingly, for the purpose of analyzing the frequency of a received signal on the spot, operators have to carry many units such as the frequency analysis apparatus 130, low-noise amplifier 120, power supply 140, etc., thereby causing a degradation in working efficiency. Furthermore, many operators are required to perform the signal frequency analysis, resulting in an increase in maintenance costs.
Additionally, existing frequency analysis apparatuses have the disadvantage of being large in volume and weight in that they are provided with radio frequency (RF) modules and various functions. For this reason, such a frequency analysis apparatus is not appropriate to carry, although it is essential for the operation of a repeater or base station. Further, the frequency analysis apparatus is able to measure only high-level power. In this connection, a reverse mobile communication spurious component or a signal transmitted from a terminal to a base station must be received through an antenna, amplified through a low-noise amplifier and then analyzed by the frequency analysis apparatus. As a result, a large amount of equipment is required for the signal analysis, resulting in a degradation in mobility on the spot and an increase in maintenance costs.
Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a card-type signal power detection device which has a low-noise amplification function therein and is capable of receiving a low-power signal and detecting the power of the received signal.
It is another object of the present invention to provide a frequency analysis apparatus which is capable of analyzing the frequency of the received signal under the condition that the above-mentioned card-type signal power detection device is mounted to a portable terminal device such as a notebook computer or a personal digital assistant (PDA), thereby securing mobility on the spot and reducing maintenance costs.
In accordance with one aspect of the present invention, the above and other objects can be accomplished by the provision of a signal power detection device comprising: radio frequency amplification means for attenuating and low-noise amplifying input signals; intermediate frequency amplification means for converting an output signal from the radio frequency amplification means into a desired intermediate frequency signal and detecting power of the converted intermediate frequency signal; local signal generation means for supplying to the intermediate frequency amplification means a frequency signal corresponding to the intermediate frequency signal whose power is to be detected; and digital signal processing means for digitizing the signal power detected by the intermediate frequency amplification means such that it is appropriate to an interface standard, outputting the digitized result to a portable terminal device connected thereto via an interface and supplying a desired reference frequency to the local signal generation means; the signal power detection device being of a thin card type such that it can be connected with the portable terminal device via a data interface slot.
In accordance with another aspect of the present invention, there is provided a frequency analysis apparatus comprising: a card-type signal power detection device for low-noise amplifying and filtering input signals to detect power of a signal corresponding to a desired frequency, among the input signals; and a portable terminal device connected with the card-type signal power detection device via a data interface slot for transferring a frequency command corresponding to the desired frequency to the signal power detection device, receiving the signal power, detected by the signal power detection device in response to the frequency command, storing the received signal power and displaying it on a screen. Preferably, the signal power detection device may include: radio frequency amplification means for attenuating and low-noise amplifying the input signals; intermediate frequency amplification means for converting an output signal from the radio frequency amplification means into a desired intermediate frequency signal and detecting power of the converted intermediate frequency signal; local signal generation means for supplying to the intermediate frequency amplification means a frequency signal corresponding to the intermediate frequency signal whose power is to be detected; and digital signal processing means for digitizing the signal power detected by the intermediate frequency amplification means such that it is appropriate to an interface standard, outputting the digitized result to the portable terminal device via an interface and supplying a desired frequency signal to the local signal generation means in response to the frequency command transferred from the portable terminal device.
More preferably, the signal power detection device may further include: a connector connected to an antenna for receiving an external signal through the antenna and transferring the received signal to the radio frequency amplification means; and signal shield means formed on an external surface thereof for shielding external signals.
Preferably, the interface standard may be a personal computer memory card international association (PCMCIA) standard, mini peripheral component interconnect (PCI) standard or universal serial bus (USB) standard.
Preferably, the portable terminal device may be selected from a group consisting of a personal digital assistant (PDA), a notebook computer and a Web pad.